Process of recovering sulfur in elementary form from pyrite.



v UNITED STATES PATENT OFFICE.

GILBERT RIGG, OF PALMERTON, PENNSYLVANIA, ASSIGNOR TO NEW JERSEY ZINC COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

PROCESS OF RECOVERING SULFUR IN ELEMENTARY FORM FROM IYRITE.

No Drawing.

To all whomit may concern V Be it known that I, GILBERT Rico, :1- sub.

ject of the King of Great Britain, residing at Palmerton, county of Carbon, State of Pennsylvania, have invented certain new and useful Improvements in Processes of Recovering Sulfur in Elementary Form from Pyrite; and I do hereby declarethe following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which. it apper-- I tite varying somewhat, being given as Fe S to Fe S In the usual method of converting pyrite into pyrrhotite, the ore is partially roastedin a current of air, "thehroasting being stopped when sufficient sulfur has been driven ofi to effect the desired conversion.

If the roasting were continued beyond this.

point, the pyrrhotite would be converted into non-magnetic ferric oxid.

The objection to converting pyrite into' pyrrhotite by partially roasting in a current of air is: that the sulfur'is driven ofit'fas S0 mixed with large volumes of fire gases, so thatthe gas mixture is too dilute and too impure to be available for sulfuric acid manufacture. The gas mixture is, therefore,

usually delivered into the airand not only isthe sulfur wasted, but the gases thus discharged are very injurious to vegetation andcause much trouble. By my method, the sulfur is recovered in the form of elementary sulfur or brimstone, and all loss and nuisance are practically obviated.

In carrying the process. into eflect, I heat the pyrite or pyriti'ferous ore in a mufiie, or in a shaft, from which the fire gases and-air are excluded. At temperatures ranging from 600 C..to 800 0., the pyrite gives up part of its sulfur, which passes over as sulfur vapor, and, leaving the muffle or shaft by suitable exit openings, is recovered in the form of elementary sulfur in a suitable condenser. .The pyrite, by this treatment, is

- converted into pyrrhotite.

Specification of Letters Patent.

Application filed March 27, 1911. Serial No. 617,210. I

Patented July i4, 1914.

A further advantage of this method of treatment isthat it is impossible to pass beyond the point of converting the pyrite into pyrrhotite or magnetic sulfid. In the process at present employed, on the contrary, where the ore is roasted in a current of air, it is difficult and, with some ores, practically impossible, to interrupt the operation at the point I where sutlicient sulfur has been burned off to change the pyrite into pyrrhotite. If the roasting is not continued long enough, acertain amount of non-magnetic pyrite is left unchanged, and if carried too far. non-magnetic ferric oxid is produced, which is equally undesirable from the standpoint of converting the entire mass into pyrs rhotite. With my method, the pyrite can only change into pyrrhotite. Further heating has no effect upon it, unle$ the temperature is carried to such a degree as to fuse the charge, and this is easily obviated. Consequently, the heating can be-continued long enough to insure the complete conversion of the pyrite into pyrrhot-ite without incurring any danger from over-roasting.

Having thus described my invention,- what I claim is: v 1. The process of converting pyrite into pyrrhotite, which consists in expelling by heat, in the absence of air, a. portion ofthe sulfur from the pyrite at temperatures main tained below the fusion point of the pyrite until the pyriteis converted into pyrrhotite,

that is to say, into magnetic sulfid; substantially as described.

2. The process of converting pyrite into pyrrhotite, which consists in expelling by heat. in the absence of air, a. portion of the sulfur from the pyrite at temperatures main-' tained below the fusion point of the pyrite until the pyrite is converted into pyrrhotite that is to say, into magnetic sulfid, said temperatures. ranging from 600 C. t0 800QC.; substantiallyas described.

In testimony whereof I afi'ix my signature,

in presence of two witnesses. V

GILBERT RIGG.

Witnesses:

HENRY HABDENBERGH, E. G. TACY. 

